Plus detergents



United States Patent OfiFice Re. 26,134 Reissued Jan. 3, 1967 26,134 MINERAL OIL COMPOSITION Joseph E. Fields, Ballwin, and John H. Johnson, Kirkwood, Mo., assignors to Monsanto Company, a corporation of Delaware No Drawing. Original No. 3,201,351, dated Aug. 17, 1965, Ser. No. 116,247, June 12, 1961. Application for reissue Mar. 18, 1966, Ser. No. 538,144 8 Claims. (Cl. 252-56) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

The invention relates to mnieral oil compositions having oil-soluble isobutylene/fumarate polymers therein.

Favorite heavy duty detergent additives presently used in motor oils for automobiles are additives containing large amounts of barium. It has been found that a number of commercially available viscosity index improvers and pour point depressants are not stable or compatible in the presence of these barium detergents which are basic in nature with the result that the engine oils containing mixtures of these additives steadily increase in viscosity and may eventually gel. A new type of viscosity index improver and/or pour point depressant which is an isobutylene/fumarate polymer has been discovered and very surprisingly this new additive is quite stable and compatible with the barium detergent additives in mineral oils.

It is an object of this invention to provide new and improved viscosity index improvers which are stable in mineral oils in the presence of barium or other basic detergent additives.

It is another object of this invention to provide new and improved pour point depressants which are stable in mineral oil in the presence of barium or other basic detergent additives.

It is another object of this invention to provide new and improved viscosity index improver and pour point depressants which are stable in mineral oil in the presence of barium or other basic detergent additives.

These and other objects of the invention will become apparent as the detailed description of the invention proceeds.

The compositions of the invention have mineral oils as the major component, i.e. in excess of 50% by weight of the compositions, and minor amounts at least suificient to increase the viscosity index substantially and/or to lower substantially the pour point of the base oil of oil-soluble polymers of isobutylene and alkyl fumarates. Other monomers in minor amounts can also be polymerized with the isobutylene and fumarates to form useful compositions. Also other oil additives can be present in the mineral oil, especially barium detergent additives, if desired. The isobutylene/fumarate polymers are present in the composition of the invention in concentrations ranging from about 0.05% to or more, preferably from 0.1% to 0.5% when pour point depressing is the primary object, and a larger concentration for example, from 0.5% to 10% when viscosity index improvement is the primary object. It can be desirable to incorporate the isobutylene/fumarate polymers in mineral oils in substantially larger amounts up to 50% preferably from about 20 to about 40% by weight based on the mixture of the mineral oil and polymer, as a concentrate useful in blending back with mineral oil for actual use, e.g. as a motor oil for automobiles. For good viscosity index improving properties normally it will be preferred to use a polymer having an average molecular weight within the range of about 15,000 to about 100,000 preferably 20,000 to about 70,000; however, higher and lower molecular weight polymers will be operable. For pour point depressant uses it is preferred that the molecular weight of the polymer be below about 10,000, polymers having molecular weights of 2,000 to 3,000 being quite satisfactory, although 15,000 to 20,000 or higher molecular Weight polymers will be eflective as pour point depressants. The useful polymers of the invention must of course be soluble in the mineral oil in amounts and over the temperature range at which the mineral oil composition is to be used and normally preferred polymers will be soluble in mineral oil, e.g. an SAE20 grade mineral lubricating oil to the extent of at least about 1% by weight at room temperature. To insure that the polymers will be soluble in mineral oil, the average number of carbon atoms in the alkyl groups of the fumarate should be at least about 6.5, preferably in excess of about 7.0. These polymers of fumarate and isobutylene are substantially 1:1 molar isobutylene to fumarates regardless of the ratio of the monomers charged in the process of producing the polymers, and normally a molar excess of isobutylene will be used in the process. For pour point depressant use a mixture of straight-chain alcohols ranging from about 8 to about 24 carbon atoms, preferably from about 10 to 18 carbon atoms should be used to esterify fumaric acid making the fumarate monomers. For the purpose of this application lower alkyl is defined as 1 to 6 carbon atoms and higher alkyl as 8 to 24 carbon atoms.

An illustrative listing of suitable fumarates to choose from as comonomers with isobutylene is set forth below as follows: dimethyl fumarate, diethyl fumarate, methyl ethyl fumarate, diisopropyl fumarate, di-t-butyl fumarate, methyl n-butyl fumarate, di-n-bntyl fumarate, di-isobutyl fumarate, di-n-amyl fumarate, di-n-hexyl furnarate, di-nheptyl fumarate, di-n-octyl fumarate, di-Z-ethylhexyl furnarate, diisooctyl fumarate, di-n-decyl fumarate, dioxodecyl fumarate, butyl n-decyl fumarate, di-n-dodecyl fumarate, di-t-dodecyl fumarate, di-oxotridecyl fumarate, di-Lorol fumarate, di-tallow fumarate, di-n-eicosyl fumarate, et. Tallow fumarates are obtained by esterifying fumaric acid with a mixture of about 67% by weight of C and 33% by weight of C straight-chain alkyl alcohol. Di-Lorol fumarates are obtained by esterifying fumaric acid with a mixture of 3%C 6l%-C 23%- C 11%C and 2%C straight-chain alkyl alcohols.

An illustrative list of third types of monomers which can be polymerized with isobutylene and fumarates to form polymers which have special properties such as low temperature detergency or other properties in addition to high viscosity index and low pour point are the following: styrene, both higher and lower alkyl methacrylates such as methyl methacrylate, vinyl acetate, isopropenyl acetate, vinyloxyethanol, vinyl ethyl ether, B-hydroxyethyl butyl fumarate, fi-hydroxyethyl Adol 14 fumarate, dimethylaminoethyl butyl fumarate, diethylaminoethyl Adol 14 fumarate, and the like.

The invention will be more clearly understood from the following detailed description of specific examples thereof.

EXAMPLE 1 fied by dissolving in benzene and precipitating from methanol. g. the following results:

Yield of purified polymer was 75.4% (21.4 An elemental analysis of the purified product yielded Found Theoretical 0, percent. 67. 4 67. 6 11, percent.. 10. 1

A number of other experiments were carried out wherein isobutylene was copolymerized with various fumarates and mixtures of fumarates.

The data from 15 these experiments is summarized in Table I below.

Table 1 Run No.1 Run No.2 Run No 3 Run No. 4 Run No. 5

Monomers IB/Elllll IlilE FloDF. IBll'umoratc mole charge ratio 0: 4:1. Product composition, mole ratio... :515. Fumarates, average No. ulkyl carbon atoms. 0.0. Mole Percent Catalyst. 0.8% B2 0 Pressure, p.s.i.;:... Autogcnous. Temperature, (3.. 75. Time, hours 24. Yield, pl rcnt. 87.5 Percent polymer in cone. of Bose Oil 1. 30. Oil vise. 111 Base (Jil13%polymer Kinemutic vise, rs:

At 100 F 97.6. At 1210 F.. 11.91. Specific viscosit.1t..

Emulsion Emulsion hexane 20% hexane polymer. polymer. polymer. solvent. solventdmm.

Run No. 6 Run No. 7 Run No. 8 Run No. 9 Run No.10 Run No.11

Monomers IB 'EF 'ODF.... IWEF/ol)F.... IlilEF/ol)1 IB/EF/oDF.. IBJEF/QDF- IB/EF/nDF. IB/fumnrnte mole charge ratio 12. 121 12:1..... 12:1. 12:1 12:1. Product compositiOl], mole at 10:515. 10:515. Fumarntes, average No. alkyl carbon 60. 6.0.

atoms. Mole percent catalyst 0.8% 132202 0.8% 112202 0.8% B2202 0.8% B2209 0.8% B2 0 Pressure, p.s.i.g.... Autogcuous. Autogenous. Autogenous Autogcnous 400001;). 'Iempernture, 9.. 2 T0 70 1111 70. Time, hours. 24. 18. Yield, percent 94.3. QSAc. Percent polyrn. in cone. of Base Oil 1. 4t) Oil vise. in Base Oil 2, 3% poly1ner Kinematic visco tv, 05.:

AtF. 125.17.-... 111.15 At, 21o" F. '.40

0.212. 0.293. Etficiency. 1.377. \".I 210.31.... 1322.5 110.6. Remarks 7.5% polymer in 11 tile insol. oil l-Iaze Base Oil 3. 11011-i01l111l11g.

Run No. 13 Run No. 14 Run No. 15 Run No. 16 Run No. 17

Monomers IBi'EF/IHJF. IB/EF/nDF. 1B iumarato mole ell-urge ratio. 12: 1.. 12: 1. Product composition, mole ratio. 10:4:0 10:515. Fumarates, average No. alkyl carbon 6.0.

atoms. Mole percent catalyst 0.8972. llmOz 0.0% 117.20! 0.8% 112202 0.8 1, l)("l1r.zt)g.. 0.8% l)(.B7. 0 0.8% DQ111 0 Pressure, p.s.i.g Autogenous. .\utngenuus A utogenous. Autogenous. Autogenous. Autogenous. Temp. C "0 70.. 50 50 50. Time, hours. 40. Yield, percent Percent polymer in 1 no. of Base 011 1. 01.] visc. in Base Oil 2. 3% polymer- Kinenuttir viseosities, cs.:

At100 F. 110.94 At 210 F... ]3.23 Specific viscosities:

At 100 0.210. At 310 F. 0.405. Elllcieney 1.020. \',I 1142.... 110.11 127.7. Remarks Oil non-foaming Uil noirfoaming Oil non-mulling lnsol. at room haze. temp.

Table 1-Continued Run No.18 Run No.19 Run No. Run No. 21 Run No.22 Run No.23

Monomers IB/Enl) IBJE F/AHF. IBiEF/A F. IBIEAHF. Ili/Iurnarate mole charge ratio... 12:1 4:1 4:1. 12:1. Product composition, mole ratio. 1:1. 1:1v Fuitnarates, average No. alkyl carbon 6.0 7.5.

a ems. Mole percent catalyst 0.8% I)CBZ202. 0.8% DCBMOL. 0.2% DCBZ2OL 0.4% DCBZzO:|.. 0.4% DQ131202 0.8% DCBz Og. Pressure, p.s.1. Autogenous- 25,000-IB.. Autogenous... Autogenous Autogenous. Temperature, C 50 50 50 50. Time, hours 24. Yield, percent. 100:: Percent polymer in cone. 01 Base Oi] 1- 40. Oil vise. in Base Oil 2, 3% polymer Kinematic viscosities, cs.:

At 100 F-.. 127.84-. 135.07. At 210 F... 15.21 Specific viscosities:

At 100 F.-. 0.394-.." 0.475. At 210 1". 0.474. 0.970. 0.998. 119.9-.- 115.3... 117.0. Oil non-ioam- Oil non-foam- Insoluble h. ze N on-foaming ing. ing. oil.

Run No. 24 Run No. 25 Run N0. 26 Run No. 27 Run No. 28 Run N0. 29

Monomers IB/EF/EAHF IBJBFJAHF. IB/BF khrF- IBIEIII/BF/ IBIELFJTXF IBJBA F.

A14 E. 14F. lBjfumarate mole charge ratio. 4:1 4:1 :1 4:1 Product composition, mole ratio 10:5:5.. 10:05:13.5. Fuinarates, average N0. alkyl carbon 85. 7.15

atoms, Mole percent catalyst 0.4% DCBzzOr. 0.4% DCBzzOz. 0.2% DCBzzOz.. 0.4% DQ13220 0.4% DCl'izzO 0.4% DCBZ O Pressure, psig Autogenous... Autogenous...-. g5,000IB.. Aut0genous Autogcnous. Autogenous.

'lemperature, C Time, hours. Yield. percent.

Percent polymer in cone. of Bose Oil 1 Oil vise. in Base Oil 2, 3% polyn10r- Kinematic viseosities, 05.:

Eilieienq 1.002. 1305.... 118.4 Remarks Insoluble. not Insoluble haze run.

Run No.30 Run No. 31 Run No. 3'. Run No.33 Run No. 34 Run No. 35

Monomers IBIBPJBAHY Ill/BFIBAHF IBfBF/BA F IBIUF BA F IB/EFjBA F IlhBF/A F. llljiulnm'ate mole charge ratio.. 4:1 4:1 4:1 4:1 4:1 4:1. Product eomposition, mole ratio 10:0:4. Forum-ares, average No. ulkyl carbon 6.7- 7.6.

atoms. Mole percent catalyst 0.4% DCBHOL. 0.4% DCBZ2O7.. 0.4% DCBZQOL. 04% 130112110 0.4% 11002 0 0.4% llfllz O Pressure, p.s.i.g Autogcnous. Autogcnous. Autogenous..... Autogenous.-.. Autogeuous. Autogenous. Temperature, C 50 50 50 50. Time, hours 24 24. Yield, percent 1000. 100c. Percent polymer in cone of Base 011 1 28.0. 40. Oil vise. in Base Oil 2. 3% polymer Kinematic viscosities, cs: At 100 F- 127.01 140.07

LEGEND Polymer system:

IB-Isobutylene EF-Diethyl furnarate BF-Dibutyl fumarate ZEHF-Z-ethylhexyl fumarate oDF-Di-oxodecyl fumarate nDFDi-n-decyl furnarate A FDi Adol 14 furnar-ate (fumarate prepared by esterifying fumaric acid with a mixture of straight chain alcohols of the following composition: 3%-C 65.7%C 20.2% C 10.6%-C and C18) EnDFEthyl-n-decyl fumarate EA F-Ethy1 Adol 14 fumarate BA FButy1 Adol 14 fumarate SM-Styrene IPAc-Isopropenyl acetate VAcVinyl acetate LEGENDContinued Polymer system:

VOEB-Hydroxyethyl vinyl ether of vinyloxyethanol VEEVinylethyl ether Catalyst:

K S O -AOTPotassium persulfate-Aerosol OT Bz O Benzoyl peroxide DCBz o Dichlorobenzoyl peroxide Pressure:

AAutogenous (isobutylene) 4000 H O4000 p.s.i. maintained with water 4000 IB4000 p.s.i. maintained with isobutylene Yield: Those marked determined by materials balance from oil concentrate preparation. All others determined by polymer precipitation from alcohol Base Oil No. 1:

This is a solvent refined Mid-Continent petroleum lubricating oil having the following properties:

Viscosity at 210 F., cs. 3.94 Viscosity at 100 F., cs 21.58 Viscosity index 75.3 Specific gravity, 25/25 C 0.886 Flash point, Cleveland open cup, F. 375

Base Oil No. 2:

This oil is a solvent refined Mid-Continent petroleum lubricating oil having the following properties:

Viscosity at 210 F., cs. 10.39 Viscosity at 100 F., cs 91.73 Viscosity index 103.4

Flash point, Cleveland open cup, F. 450

Base Oil No. 3:

This is a mineral hydraulic designed to meet Government specification of MIL-O-5606 as follows:

Pour point, F 75 Flash point, minimum, F. 200 Viscosity at 100 F., cs 3.80 Viscosity at 210 F., cs 1.37 Viscosity index 94.6 Specific gravity, 60/60 F. 0.862

Remarks: HazeBorderline solubility at room temperature.

The legend set forth above after Table 1 is applicable to Table 1 and the other tables which will be set forth below.

EXAMPLE 4 This is a detailed description of Example 4 which is summarized in Table 1 above. The reactor was a small steel bomb, which was flushed with nitrogen and chilled in an ice bath. To this steel bomb were charged 52.6 g. of di-oxodecyl fumarate, 44.6 g. of isobutylene, 20 ml. hexane and 0.6 g. of benzoyl peroxide. The bomb was then capped and tumbled in an air oven at 75 C. for 24 hours. Then the bomb was rechilled in Dry Ice, opened and any excess isobutylene allowed to evaporate upon warming to room temperature. The hexane was removed and the polymer purified by dissolving in benzene and precipitating from ethyl alcohol. Pressure during the run was autogenous pressure generated by isobutylene at the temperature of reaction. Yield of polymer product was 93.3%. A sample of the polymer product was dissolved in Base Oil No. 1 to make a 30% concentrate. This 30% concentrate was diluted to 3% polymer with Base Oil N0. 2 for viscosity measurements. The results of the viscosity measurements are reported in Table l.

8 EXAMPLE 10 This is a detailed description of Example 10 summarized in Table l. The reactor used in this experiment was a magnetically stirred reactor called a Magne-Dash reactor designed for high pressure operation. To the Magne-Dash reactor were added 118.6 g. of isobutylene, 34.9 g. of di-oxoclecyl fumarate, 15.2 g. of ethyl fumarate and 0.6 g. of benzoyl peroxide. The reactor was then flushed with nitrogen and pressured up with water to 3500 p.s.i.g. Reaction period at 70 C. was 24 hours. The 3500 p.s.i.g. was not maintained since the run continued overnight and the next morning the pressure was 300 p.s.i.g. in the bomb. The polymer was dissolved in 117.5 g. of Base Oil No. 1 and 400 ml. of benzene. The water and benzene were removed under water pump vacuum to a pot temperature of C. Yield of polymer was 57.6 g. (96.1% yield). An additional 16.9 g. of process oil was added to make the 30% concentrate. A sample of the polymer concentrate was diluted to 3% polymer with Base Oil No. 2 for viscosity measurements. The resulting oil was hazy indicating insolubility of the polymer and the oil was non-foaming. In this experiment a little too much ethyl fumarate was used as indicated by the insolubility, the average number of alkyl carbon atoms being 6.0.

EXAMPLE 20 This experiment was carried out in a high pressure rocking type bomb. To the bomb were charged 71.25 g. of di-Adol 14" fumarate, 23.84 g. of diethyl fumarate, 62.1 g. of isobutylene and 0.82 g. of 2,4-dichloro benzoyl peroxide catalyst. This catalyst contained 50% of the active ingredient, the peroxide. The bomb was then pressured up to 25,000 p.s.i.g. with isobutylene and maintained at 50 C. for 13 hours. For the last 4 hours of reaction time giving a total time of 17 hours the reaction mixture was maintained at 60 C. To the polymer product was added Base Oil No. 1 to make a 40% concentrate of the polymer. Excess isobutylene was then stripped otf the polymer concentrate and an additional 15 g. of the oil added to readjust to 40% polymer concentrate. Yield was 93.6% polymer.

EXAMPLE 29 The procedure and equipment used in this example was the same as was used in Example 4. To the small bomb was charged 31.5 g. of isobutylene, 52.1 g. of butyl Adol l4" fumarate and 0.9 g. of 2,4-dichloro benzoyl peroxide (50% active). Pressure in the run was autogenous established by the presence of excess isobutylene. Reaction temperature was 50 C. and polymerization run time was 24 hours. At the end of the polymerization run Base Oil No. 1 was added to the polymer to make a 30% concentrate and the usual stripping and readjusting of the base oil was carried out to establish the 30% polymer concentrate in Base Oil No. 1. As usual a sample of the 30% concentrate was diluted with Base Oil No. 2 to 3% polymer for viscosity measurements.

EXAMPLE 41 This example describes the preparation of an isobutylene fumarate polymer containing a third monomer. The experiment was carried out in equipment and in a manner similar to that described in Example 4. To the small bomb was charged 17.4 g. of isobutylene, 2.6 .g. of isopropenyl acetate, 53.1 g. of di-Adol 14" fumarate and 0.63 g. of 50% active 2,4-dichloro benzoyl peroxide. The pressure was autogenous established by the presence of excess isobutylene, reaction temperature 50 C. and reaction time 5 days. Base Oil No. 1 was added to the polymer product to make up a 40% polymer conoentrate and the usual stripping and oil adjusting carried out. Yield was 98.0%. A sample of the polymer concentrate was diluted with Base Oil No. 2 to 3% polymer and viscosity measurements were made.

In Table 2 below are summarized a number of runs wherein isobutylene and fumarates are polymerized with a third monomer. Run 41 of this table is discussed in detail above. In column 3 of this table a 4:1 molar 10 sembly, 1-71 Series, No. 5154288; with injector No. 5226710; operating at 1800 cycles per minute.

In a pre-test flush, the glass reservoir of the equipment is filled with test fluid to the level of the supporting excess of isobutylene is shown and this means a 4:1 ex- 5 ring; about 200 ml. of test fluid. The injector bleed valve cess over the sum of the number of moles of the fumarate is opened and the equipment is allowed to drain until plus the third monomer. liquid flows. An empty 600 ml. beaker is placed under Table 2 Run No. 38 Run No. 39 Run No. 40 Run No. 41 Run N0. 42 Run No. 43

Monomers IBIVOEIAMF IBIVOE/A F !B/IPAc/A F.- IBlIPAc/A |F. IBNEE/AHF IBfVEE/AnF. IB/iunuu'ate mole charge ratio... 4:1 4:1 4:1 4:1. Product composition,1nle ratio. 321:4 2:2:4 311:4 2. 3:1:4. Mole percent catalyst w DCBZz 0.4% DCBz O 0.4% DCB O 0.4% 13081 0 0.4 DQ132201" 0.4% DC B2202. Pressure, p.s.i.g Aut0genous Autogen0us Aut0genous Autogenous Autogen0us.. Autogenous. Temperature, C 50 50 t) 50 50 50.

Yield, percent Percent polymer in cone. of Base Oil 1.

Oil vise. in Base Oil 2, 3% p0ly1ner Kinenitic viscosities, cs:

EXAMPLE 45 This experiment describes the preparation of a polymer having no isobutylene therein. The experiment was carried out in the same type of equipment and in the same manner as Example 1. To a Coke bottle were charged 24.65 g. of di-oxodecyl fumarate, 5.35 g. of vinyl acetate, ml. of hexane and 0.3 g. of benzoyl peroxide catalyst. Reaction temperature was 75 C. and reaction time 24 hours. A concentrate of polymer and oil was made in the usual manner and the volatiles stripped off. Yield of polymer was 94.7%. A sample of the 30% concentrate was diluted with Base Oil No. 2 to 3% polymer and viscosity measurements were made.

In Table 3 below are summarized a number of runs of polymers made containing fumarate monomer plus another monomer but no isobutylene monomer. Run 45 described in detail above exemplifies these experiments.

the double discharge tube. Oilers are opened on the machine and adjusted to several drops/minute. Then the motor switch is turned on. The motor switch is turned off when the fluid level reaches the neck of the reservoir. (This will prevent the introduction of air into the feed system.) The reservoir is once again filled with the prc-test flush fluid and the above sequence of steps repeated.

Now the equipment is ready for the regular shear test. A fresh sample of the test fluid is poured into the reservoir (minimum of 150 ml. plus ml. for each intermediate sample to be taken). The rubber connector hose between the reservoir and the machine is squeezed to expel any air trapped therein. A clean 600 ml. beaker is placed under the discharge nozzle. Then the motor switch is turned on. The motor switch is turned off 'when the fluid level reaches the neck of the reservoir.

Table 3 Run N0. 45

Run No. d6 Run No. 47 Run No. 48

Monomers Molar charge ratio. Solvent Catalyst and weigh Hexane 8 wt. percent oDF/VAc 1:1

Hex-tine 3 wt. percent Temperature, C 75... Time, hours. 24 Yield, percent 94.7- Percent polyn n cont. of Base Oil 1 Oil vise. in Base Oil 2, 3% polymer- Kinematic vise. 05.:

At. 100 F At 210" F Specific vise.

At 100 F At 210 F 0.358- Etliciency 1.270 v.1 1205 0D F/EF 80:20 wt. percent Hexane- 3 wt. percent,

01) F/IPAc 1:1 Hexane 3 wt. percent oDFjSM. 1:1.

Hexane. 3 wt. percent 111.7 30% oil conc 30, oil come.

In Table 4 below the results of shear tests are compared between a polymer of the invention, the product of Example 20, and Acryloid 71 0 which is a good commercial viscous index improver having satisfactory shear.

The shear test is a diesel injector shear test. This test is used to evaluate the viscosity-stability of fluids. This is accomplished by passing the fluids through a diesel injector for a number of cycles. The actual diesel injector test machine used was a General Motors diesel head as- The beaker of sheared fluid is removed and stirred or mixed lightly to collapse any foam. Then approximately 1 ounce of the sheared fluid is poured 011 into a fourounce bottle it a sample is desired. The remainder of the fluid is poured back into the reservoir. The above cycle of steps is repeated until the desired number of cycles has been run (normally ten to twelve cycles are necessary. Further shearing results in little additional viscosity decrease).

The viscosity of the samples is determined and the results are reported as percentage change of viscosity from the original fluid viscosity. It is desirable to shear a known reference fluid for comparison to the unknown dimethyl formamide at 25 C., which polymer was esterified with a mixture of straight-chain alcohols having 0.1. determined from a 1% solution of the polymer in 2.5%C10, 55.5%-C12, 21.0%-c 4, 10.2%-C1fl and fluids. 10.8%C alcohols therein. The particular detergent After the completion of the shearing run the motor additive used in compatibility tests of Table 5 was adeterswitch is turned on and the system is run dry, then three gent prepared from a 0.1 specific viscosity ethylene/maleic l00-ml. portions of Stoddard solvent is used to flush out anhydride copolymer similar to that used for pour dcp. the system A, which polymer was esterified to the extent of about 65% with a mixture of straight-chain alcohols having Table 4 3.0%C10, 65.7%C12, 20.2%C14, 10.6%-C and 0.5%-

C alcohols and the balance of the esterification being acv complished with N,N-dimethyl-l,3-pr-opylenediamine to Scosmesin Base 3% polymer give a 65/35 ester imide copolymer. In addition to pour 15 depressant A, two other pour point depressants were Monomers f pen-mt tested for compatibility with the isobutylene/fumarate 1 3g? polymers. The first of these pour point depressants is a 139mm shear After shear commercial additive Acryloid 150 which is a methacrylic ester polymer, and the other of these additives is another IBIEFIAHFHHU 19.40 73 5 g7 20 commercial pour point depressant called Santo-pour C." Acrylvid 56 12 58-24 It will be seen from an examination of Table 5 that the isobutylene/fumarate polymers are compatible in con- 1ACommercialnolymcthacrylate vl-impmvfir' centrated oil solutions with pour depressant A and the detergent additive but are not compatibile with the Acrylt is seen from Table 4 that the polymer of the invenloid 150 and the Santopour C polymers. In dilute tion has as good or somewhat better shear properties than solutions (up to 57% total additive) all additives were the commercial V.I. improvers. compatible with polymers of the invention, however.

To test the compatibility in concentrated solutions of In Table 6 below is set forth a comparison of the hyisobutylene fumarate polymers of the invention with drolysis stability of a number of different additives with some other lubricating oil additives, mixtures of additives the isobutylene fumarate additive of the invention. In were made and compatibility observations carried out. this hydrolysis method a 2 to 2 weight percent polymer The results of these compatibility tests are summarized solution mol xyl eq i as made up in Table 5 below, in 250 ml. of benzene/isopropanol (1:1 by volume), and Table 5 IB/fumarnte Compatibility ratings N 0. Pour Low temp.

depressant detergent Run No. Monomers 1 hr. 1 day 5 days 1 week 4 weeks 8 weeks 15 IBjnDF t. Pour dep.A Clear Clear Clear t. Clcar Clear Clear-com- 15 IB/nDF H Detcrgent do do do do "do i i o i l1 IB/EF/nDF Pourdep.A do V.sl.hazc V sLhazei. V.sl.hnze. V.sl.l1aze V.sl.haze. 11 lB/EF/nDF Detergent... d0 Clear Clear Clean..." Clear Glenn-coin 10 IB/EF/oDF Pourdep.A- meow do .410 d0 "do H i iiii l0 IB/EF/ol)F A. Detergent." ...(lo. do do ...do do Do. 14 IB/EWnDFhUH Acryloid 150-. Hazy... liazywnn Z-ltiyQrsHH tttttttttttttttttttt t, 14 lB/EF/nl)F SautopourC l0 Turhid Turbid 2lnyn1's. W

V. s]. means very slight.

In Table 5 the composition of all blends was adjusted to give 15 parts of pour point depressant polymer or low temperature detergent polymer to 100 parts of V.I. improver (isobutylene/fumarate) polymer giving a total of 115 parts of polymer additives as a 30% concentrate in Base Oil No. 1. Pour dep. A was an ethylene/maleic anhydride copolymer having a specific viscosity of about to this solution was added 0.05 mol of potassium hydroxide. This mixture was then heated at C. during the duration of the test with samples being withdrawn periodically for determination of potassium hydroxide consumption. Blank experiments were run at the same time as the polymer experiments. These hydrolysis tests are summarized in Table 6 below.

Table 6 Fumaratc, Percent hydrolysis alter specified time Run Polymer av. N0. alkyl r i n.. ..,.n A

No. carbon atoms 0.5 in. 1.0 hr. 4.0 hrs. 8 0 hrs 24.0 his 1 80. 0 "A t t t t t t t u t t t r t t t t l2 13 15 17 .21

[i5 TL! t r. l 34 42 4!) 51 H 27 33 10 45 53 Ill/BF (1:1) -c 4.0 1 3 W 4 Iii/2 EllF(l:l) 8.0 5 7. ti 7 13 DF H 10. 0 9 .1 t) 9 9 10.0 15 17 n 20 22 10. 0 9 11 l" H 15 6. 0 l2 l4 16 21 t). 0 10 13 14 15 6. 8 8 l4 (i, 0 7 12 2 a a W 2 100 uuuuuuu 17 54 3 Using 3 equivalents of KOII.

In Table 6 a number of different polymers are compared with polymers of the invention in hydrolysis stability. The Acryloid 710 is a commercial polymethacrylate V.I. improver and the EMA Lorol ester is an ester of ethylene/maleic anhyd ride copolyrner wherein the alcohol used was a mixture of long-chain straightchain alcohols marketed under the trade name Lorol. Other polymers can be identified from the legend set forth after Table 1 or the detailed description in Table 6. It will be noted that none of the polymers which are not polymers of the invention even compare in hydrolysis stability to the polymers of the invention except the Acryloid 710, which is a good commercial V.I. improver of satisfactory hydrolysis stability. It will be further noted in analyzing the data of the table that optimum hydrolysis stability is attained by certain combinations of isobutylene and certain fumarate mixtures.

The superior hydrolysis stability of polymers of the invention is especially demonstrated in the presence of barium detergents and compared with one Well known type of VI. improver in Tables 7-13 below. The two commercial V.I. improvers are Paratone 430 and 460 which are copolymers of vinyl acetate and fumarates. The comparison is made by incorporating a Paratonc or 2. VJ. improver of the invention and one of three different barium detergents in Base Oil No. 2 in the normal amounts in which these additives would be added to a mineral lubricating oil in use. The stability of each of these additive blends in mineral oil is checked after varying storage periods at room temperature or C. by measuring viscosities at and 210 F. Increasing viscosity provides indirect evidence of hydrolysis and the greater the rate and amount of viscosity increase up to gelation, the more unstable is the additive combination.

Table 7 PARATON E 430" PLUS DETE R G ENTS Specific viscosity Percent specific Percent viscosity increase Par-atone 430" Percent Ba detergent Blending 100 F. 210 F. 100 F. 210 F.

Amoco 1521": 2' r. 0. 085 0. 083 Experimental Be detergent: 2% 0 036 0. 029

0. 600 3% 0. rm i 3% (l. 000 0. cs5

(0. 77500 c e 3% 1. 003 Z. 07- 37. '2 105. 0 3% 1. 037 '2. 814 111v 2 17 2 3}; 3. 104 4. 3-10 300. 5 331. 4 4. 005 5. was 410.8 424.1, 3% 4. 648 0. 182 499. T 513. 3 (0. 720)c (0 954)(: e e 3% 0. 890 1 700 .13. 4 87. l 3% 1 215 1 053 (i7. 4 7'3. 3 1 439 2 007 105. 1 110. 4 3% 72 1111*00 (T, 1 1.1573 2 314 130. 4 1312.1 3% 108 l1t'.ti0 C a. 1. 807 2 401 157. J 158. 0 3% 1. 049 1 508 52. (I 09. 5 1 177 1 583 70.15 71.1 3% 1 372 1 77-1 98. 8 01. S 3% 1 552 2 007 124.0 117. 0 3% 1. 749 2 .171 153. 5 145. b

1 RT means room temperature. V c(lorl'ected [or viscosity contribution of detergent Table 8 PARATONE 4G0 PLUS DETERGENTS Specific viscosity Percent specific Percent viscosity increase Iaratone 460" Percent Ba detergent Blending 100 F. 210 F. 100 F. 210 1*.

(0. 92$)e (1. 30410 c e 3% L6 hr.RT l. 273 5. 03011 37. 8 200. 4 1 lit-00 C. J. 158 4.1121.) 133. 8 201.5 3% 3. 389 6. 871 207. l 403. 7 3% 5. 449 8. 835G 100. 4 547. T 3% 2% a a a 0. 412 10. 337G 594. 3 65.. 8

Experimental 11a (0 8 1) (1 3m) detergent: 7 c c e e 3% 2 1. 007 2. 304 22. 1 75. 0 3% 1. 377 2. 296 57. [i 75. 2 3% 1. 878 2. 757 114. .1 110. 5 3% 2. 123 3. 061 142. 0 133. T 3% 2. 301 3. 292 103. 3 151. 3 3% 1 275 2. 114 52.1 05. 0 3% 1 408 2. 78. 8 0S. 0 3% 24 inn-00 (L 1 002 2. 330 101. 9 B1 9 3% 72 biz-00 C, 1 881 2. 550 124. 5 .10. 5 3% 108 1111*00 (l 2. 002 2. 684 138. 9 100. 5

1 RT means room tenmerature. G(1el1cd out in 210 F. viscosity tube after 30410 minutes. e-Correeted for viscosity contribution of detergent.

Percent specific viscosity increase Speeific viscosity Table 9 Blending 1hr.RT 1

Percent Ex. 20

Percent specific viscosity increase T E Ii G EN T S Specific viscosity 1 RT 111011115 room temperature.

eCorreeied for Viscosity contribution of detergent.

Percent Ex. 26 Percent Ba detergent 1 RT means room temperature.

e-Correeted for viscosity contribution of detergent.

In the Tables 7-13 above a number of different additives are defined by trade names. Paratone 430 and Paratone 460 are both vinyl acetate/fumarate copolymers, the latter being of higher molecular weight than the former and possibly being made of different fumarates. The detergent additive Amoco 121" is a basic barium detergent lubricating oil additive which is a P S -hydrocarbon reaction product containing an appreciable amount of barium. The experimental barium detergent is a different type of material than the Amoco 121" but does contain an appreciable amount of barium. The last of the barium-containing detergents is another commercial additive Santolube 333, and this commercial detergent differs chemically from both the experimental bar ium detergent and the Amoco 121. Upon examining the data of Tables 7-13 it will be noted that the Amoco 121" is in general more reactive with the V.I. improvers than the other two detergent additives. A further examination of the tables indicates that both Paratone 430 and 460 are very unstable in the presence of barium detergents whereas the V.I. improvers of the invention are sufiiciently stable to be usable in lubricating oils in the presence of barium detergents. In Table 8 it will be noted that the Paratone 460 was so unstable in the presence of Amoco 121 that the entire oil gelled in a number of instances. In other words it can be concluded that whereas the V.I. improver additives of the invention are usable in lubricating oils in the presence of barium detergents, the Paratone" type V.I. improvers such as "430 and 460 are not sufficiently stable to be usable in lubricating oils in the presence of barium detergents.

Some of the additives of the invention are in addition to being V.I. improvers also pour point depressants. For example, Base Oil No. 2 has a pour point of +15 F., 0.05 weight percent of the additive of Example 19 reduces this pour point to l5 F. and 0.25 weight percent of this same additive to the invention reduces the pour point of Base Oil No. 2 to 20 F.

Although the invention has been described in terms of specified embodiments which are set forth in considerable detail, it should be understood that this is by way of illustration only and that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.

What is claimed is:

1. A mineral oil composition of improved viscosity index and hydrolysis stability comprising a major amount of mineral oil, a minor amount sufficient to improve the viscosity index of said mineral oil of oil-soluble isobutyl ene/dialkyl fumarate polymer, said dialkyl fumarate having an average number of not more than 10 carbon atoms in said alkyl groups but at least a sufficient average number of carbon atoms to give an oil-soluble polymer and said dialkyl fumarare [polymer] and isobutylene existing in a 1 to 1 molar ratio in said mineral oil composition, and a minor amount of barium-containing detergent additive.

2. A composition of claim 1 wherein said fumarate is a mixture of lower and higher dialkyl fumarates.

3. A composition of claim 1 wherein at least some of the fumarate molecules have a lower and a higher alkyl group.

4. A composition of claim 1 wherein said polymer is an isobutylene/dialkyl fumarate/isopropenyl acetate polymet.

5. A composition of claim 1 wherein said polymer is an isobutylene/dialkyl fumarate/vinyloxyethanol polymer.

6. A composition of claim 1 wherein said polymer is an isobutylene/dialkyl fumarate/vinyl ethyl ether polymer.

7. A composition of claim 1 wherein said polymer is an isobutylene/dialkyl fumarate/vinyl acetate polymer.

8. A mineral oil composition of improved viscosity index and hydrolysis stability comprising a major amount of mineral oil, a minor amount sufficient to improve the viscosity index of said mineral oil of oil-soluble isobutylene/dialkyl fumarate polymer, said dialkyl fumarate having an average number of not more than 10 carbon atoms in said alkyl groups but at least a suflicient average number of carbon atoms to give an oil-soluble polymer and said dialky! fumarate [polymer] and isobutylene existing in a 1 to 1 molar ratio in said mineral oil compositions, and a minor amount of a basic detergent additive.

References Cited by the Examiner The following references, cited by the Examiner, are of record in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,543,964 3/1951 Giammaria 252-56 2,570,788 10/1951 Giammaria 260-785 2,710,282 6/1955 Linsk et al. 252-56 2,824,836 2/1958 Smith et al 252-56 X 2,936,300 5/1960 Tutwiler et al. 25256 X DANIEL E. WYMAN, Primary Examiner.

W. H. CANNON, Examiner. 

